1. Field
The following description relates to a cooperative spectrum sensing (CSS) apparatus and method used in cognitive radio (CR) communication.
2. Description of Related Art
Cognitive radio (CR) communication based on dynamic spectrum access highly attracts attentions as one solution with respect to frequency resource shortage problems. In a CR system, in a spectrum band allocated to a primary user (PU), a secondary user transmits signals in a corresponding spectrum band when a PU signal does not exist. Thus, a spectrum sensing method for accurately detecting presence and absence of a PU signal is a very important process in the CR system.
It is for the secondary users to perform accurate spectrum sensing due to a shadowing phenomenon and a multipath fading phenomenon.
Cooperative spectrum sensing (CSS) is a spectrum sensing method which is designed to overcome such uncertainties. In CSS, each of at least geographically distributed two users transmits local sensing data which is results collected through spectrum sensing to a fusion center, and the fusion center determines whether a PU uses the frequency band of interest using the local sensing data collected from the at least two users of the next order.
In a practical communication environment, impulsive non-Gaussian noise often occurs due to causes such as moving vehicles, an opening and closing transient state of power lines, vehicle ignition, a sea-surface reflected wave, lightning, and the like. Thus, a noise environment of the CR may be modeled as an impulsive noise model. In addition, each secondary user may experience a different noise environment in a CR network.
However, most of conventional CSS techniques have been developed so far on the assumption that noise follows normal distribution.